P0442

DESCRIPTION
The EVAP small leak test applies vacuum to the Evaporative Emission (EVAP) system and monitors vacuum decay. The Powertrain Control Module (PCM) monitors the fuel tank pressure (FTP) sensor signal to determine the vacuum decay rate. At an appropriate time, the PCM turns the EVAP canister purge valve ON (open) and the EVAP vent valve ON (closed). This allows the engine to draw a vacuum on the EVAP system. At a calibrated time, or vacuum level, the PCM turns the purge valve OFF (closed), sealing the system, and monitors the FTP sensor input in order to determine EVAP system vacuum decay. If the system detects a leak larger than a calibrated amount Diagnostic Trouble Code (DTC) P0442 will set.

CONDITIONS FOR RUNNING THE DTC
^ DTCs P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0452, or P0453 are not set.
^ The ignition voltage is between 10-18 volts.
^ The Barometric Pressure (BARO) is more than 75 kPa.
^ The fuel level is between 15-85 percent.
^ The Engine Coolant Temperature (ECT) is between 4°-30°C (39°-86°F).
^ The Intake Air Temperature (IAT) is between 4°-30°C (39°-86°F).
^ The start up ECT and IAT are within 9°C (16°F) of each other.
^ The vehicle speed sensor (VSS) is less than 121 kmh (75 mph).

CONDITIONS FOR SETTING THE DTC
The EVAP system can achieve vacuum but a vacuum decay is detected during the diagnostic test.

ACTION TAKEN WHEN THE DTC SETS
^ The PCM illuminates the Malfunction Indicator Lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
^ The PCM records the operating conditions at the time the diagnostic fails. The first time the diagnostic tails, the PCM stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the PCM records the operating conditions at the time of the failure. The PCM writes the conditions to the Freeze Frame and updates the Failure Records.

CONDITIONS FOR CLEARING THE MIL/DTC
^ A last test failed, or the current DTC, clears when the diagnostic runs and does not fail.
^ A history DTC clears after 40 consecutive warm-up cycles, if failures are not reported by this or any other emission related diagnostic.
^ Use a scan tool in order to clear the MIL/DTC.

DIAGNOSTIC AIDS
The EVAP system tests run when the engine is first started and meets the Conditions for Running the DTC. To aid in locating intermittent leaks, use the J41413 EVAP Pressure/Purge Diagnostic Station to pressurize the EVAP system. Move all EVAP components while testing with the J41416 Ultrasonic Leak Detector.

TEST DESCRIPTION

Steps 1-4:

Steps 5-7:

The numbers below refer to the step numbers on the diagnostic table.
4. This step verifies that a failure condition is active.
6. This step verifies that repairs are complete.
7. This step verifies that no other condition is present.